[The previous number of these Transactions, Vol. X X X V I I , No. 2
was pubhshed on September 30th, 1943.]
TRANSACTIONS
OF THE
ROYAL SOCIETY OF TROPICAL MEDICINE
AND HYGIENE
VOL. XXXVII.
No. 3.
DECEI~BER,1943.
OPENING MEETING OF THE THIRTY-SEVENTH SESSION
held at
Manson House, 26, Portland Place, London, W.,
on
Thursday, 21st October, 1943, at 3 p.m.
THE PRESIDENT,
Sir H. HAROLD SCOTT, K.C.M.G., M.D., F.R.C.P., F.R.S.E.,
in the Chair.
PRESIDENTIAL ADDRESS.
THE
INFLUENCE
OF T H E S L A V E - T R A D E
OF T R O P I C A L DISEASE.
IN
THE
SPREAD
BY
SIR H. HAROLD SCOTT, K.e.M.G., M.D., F.I~.e.P., F.R.S.E.
Officers and Fellows of the Society.--As you are all aware, I have not for
many years been personally engaged in tropical medical research, except
historically. My predecessors w e r e so engaged and thus were able to entertain
you with detailed accounts of their personal work, new work, at all events
work the results of which were new to their audience, of new research into
abstruse chemistry, of new theories as to the causation of old diseases, new
forms of treatment and the like. T o my great regret and, I fear, your
disappointment, I am not able to do this. I cannot regale you with such
interesting things as one m or e theory on the aetiology of sprue, or the use
170
SLAVE TRADE AND TROPICAL DISEASE.
of a nev~ chemical compound with a name as long as your arm, as a trypanocide
or a spirochaeticide. Anything new on these lines, new to me I mean, Would
not be new to you, for I should have to cull the information from papers.
abstracted in the Tropical Diseases Bulletin with which you are all familiar.
I must, therefore, choose another path.
When we read of medical men in works of fiction, they always seem to
play a highly romantic r61e, whereas we in the profession know only too well
how little real romance there is in the life of a doctor, more, perhaps, in the
tropics than at home, but little enough even there.
In my address today I would like, with your permission, to draw you
away for a short time from humdrum daily routine and to ask you to go back
with me to a romantic period of tropical medicine, romantic too in history,
for we must all remember with what delight we read, as boys, tales of the sea
and the chase of slave-ships. M y thesis today is The Slave-Trade and its
t
Influence in the Spread of Tropical Disease.
Slavery and slave-trading g o back to the dawn of history. Slaves were
imported into Lower Egypt in the early dynasties ; they made up a considerable
proportion of the population of Carthage and Rome ; after the Mohammedan
conquest of Africa they were brought from the Sudan, Abyssinia and the
Zanzibar coast to northern Africa, Arabia, Turkey and Persia. All this I leave
untouched today. M y remarks will be confined to the trade which brought
slaves from West Africa to the New World. Nor shall I say anything of those
who vountarily became slaves in times of insolvency, famine or scarcity, just
as some peculiar people in this country commit a small crime about the middle
of December to ensure warm housing, good fare and entertainment at Christmas
time at Government expense, amid conditions better than they would find in
their own homes. I shall speak only of the slave by capture ; his lot was very
different. The procedure was quite simple. The prospective dealer would
go into the country of peaceable negroes--militant tribes would give too much
trouble--taking a few muskets, some spirits and a little merchandise, say calico.
He visits the most powerful chief of the district, gives him presents, keeps him
in a happy state of semi-drunkenness, tells him he wants more slaves and doles
out the muskets. The chief without much difficulty recalls an old-standing
quarrel with a neighbour and war is declared. The enemy's subjects are
captured, the ground, their own as well as that of the enemy, is left untilled,
scarcity and famine ensue and both chiefs will sell large numbers of their
subjects and the captives at a cheap rate. Another method, much favoured by
the Portuguese, was to exchange slaves for ivory in the interior, to use human
porterage--in facL human porterage was a necessity, there was no other w a y
- - t o get the ivory to the coast and then sell the porters with the ivory to the
greater gain of the ivory trader. At other times there would be raids for slaves
without any declaration of intertribal war and without warning.
In the course of capture there was often much cruelty, Many villages
Method
A.A.
g.B.
c.c.
D.D.
IL IL
To face page i~1
of stowing
slaves on board
Lower Deck
Breadth of Beam on Lower Deck
Men's Room on Lower Deck
Platforms in Men's Room
Boys' Room
F.F.
G.c.
It. H.
I.I.
g.K.
I,. L.
the ship
Broohes.
Platforms in Boys' Room
Women's Room
Platforms in Women's Room
Gun Room on Lower Deck
Quarter Deck
Cabin
Plan
of Captain
1~¢.1~.
N.N.
o.o.o.
P.P.
~.
Perry.
Half Deck
Platforms on Half Deck
Hold
Upper Deck
Extra Stowage for Women
H. H A R O L D SCOTT.
171
might have to be raided to obtain the number wanted, many of the natives
would die from injury, starvation and disease in the jungle. Those captured
would be chained to prevent their escape, with slave-forks round their necks,
haruts fastened behind their backs and attached by a cord to the master's waist,
and sometimes gagged by a wooden snaffle. The heavy mortality among them
on their journey to the coast was evidenced by the skeletons, slave-clogs and
forks strewn along the way. Underfeeding, overworking, exhaustion, disease
and cruelty might lose one-third of the total. Much of the hardship was due
to natural attempts at escape. LOVETTCAMERONobserved at one time a gang
of fifty-two women tied together in three lots; some had children in their
arms, others were far advanced in pregnancy, all were laden and covered with
weals, and scars--sheer wanton cruelty.
Yet a further loss, perhaps as much as another third, might occur at the
barracoons where the slaves were collected on the beach before transportation.
Here, too, the fatality would be high owing~to insufficient food, overcrowding,
dysentery and fevers, for they were kept in irons and roped in fours, legs
fettered, chains round their necks. The " middle passage," as the journey
from Africa to the New World was called, might be fairly easy, but in many
cases entailed much suffering. The food was usually good and if the weather
was fair they might come on deck for air and exercise, perhaps a hose-bath,
the exercise consisting of dancing to a drum. All this was arranged, not
primarily for the benefit of the negro, but because sickness and mortality among
them would reduce the owner's profit. On a " bad ship," and later, when
the trade was being made illegal, all slave-ships were bad ships, conditions
must have been truly frightful. If one cargo in three got through the adventure
paid, so overcrowding was disregarded. In the hold were stored provisions,
powder, rum and so forth; in the 'tween decks the slaves were stowed in
hundreds, the men forward, shackled at the start of the voyage, the women
and children aft, unchained., They would be thrust in till they were packed
actually in contact and might stay there, if the weather was bad, for many
days together. Some would die and the liv]ng and the dead would lie chained
together in the dark, and hunger, thirst, misery and disease, in particular
dysentery, might, on a bad voyage, kill off 70 per cent. ; the average mortality
on a favourable voyage was 11 to 12 per cent. Stories have been told of where
the packing was so close that some would have to sit between the legs of others,
and the boarding above them so low--they might be in two tiers--that even
sitting upright was not possible, and on arrival every conceivable distortion
might be observed, as a result of the long cramped posture. If lying down,
each adult was allotted a space of 5 feet 6 inches long, 16 inches wide, and
24, occasionally 26, inches between the tiers.
Woe betide any who fell sick ! According to the terms of insuranx:e, if a
death occurred on board the loss had to be borne by the owner, whereas jettisoning alive came under the head of " sacrifice of cargo " and insurance
t72
S L A V E TRADE AND TROPICAL D I S E A S E .
was paid ; so those seriously ill might be thrown overboard. After the trade
became illegal, a slaver when chased would jettison her living cargo to delay
the pursuer, or cast the slaves manacled into the sea to prevent their being
rescued to give evidence against their captors,
I will not harrow your feelings with more of these gruesome details ; I
have mentioned some so that you may understand the potentialities for transference of infection from Africa to the New World. The filth and stench
of the vessels on reaching port were sometimes such that no one could be got
to clean them and they had to be abandoned. Most of the slaves on arrival
were very emaciated, often deformed from restricted posture, half-blind from
the dark and from ophthalmia and, possibly, onchocerciasis and months might
elapse before they were fit for sale.
I have said enough concerning the slave-trade as a trade and commercial
undertaking ; to some a,romantic story, and modern minds would be inclined
to regard such an appalling instance of man's inhumanity to man as mainly,
if not entirely, romance, had we not read and heard and did we not know of
equally, nay even more, appalling systematic and sustained inhumanity in the
last 4 years on the part o f a nation which considered itself civilized.
Obviously the slave-trade and conditions under which it flourished afforded
potentialities for the spread of disease and this afternoon I would like to consider
some of them.
The study is a fascinating one, for we are often too ready to assume that
because a disease is, or was, common in West Africa and was recorded for the
first time in the New World in the seventeenth and eighteenth centuries, therefore the latter was infected by importation from the former--a very fallacious
line of argument. ,The problem is fascinating and, if I may be pardoned the
journalistic gallicism, intriguing, and I hope the instances we take for consideration this afternoon will arouse your interest and at the same time take
your minds and thoughts away for a brief period from the irksome tasks of
routine practice into the realms of medical romance.
YELLOW FEVER.
Let us start with yellow fever, the place of origin of which has been the
subject of much discussion, some people relying on historical records and
the weighing of possibilities and probabilities, others on biological arguments.
Historically, the value of the evidence of American origin must depend
very largely on the, meaning of terms used and the accuracy of translation of
ancient records. We may dismiss, as unworthy of serious discussion, the view
of AUGUSTIN that its.origin was Asiatic, for he based his view on the Martinique
outbreak of 1688-90, when the Oriflamme brought the infection, la maladie de
Siam, or to give it its more scientific but equally misleading name, typhus
miasmatique putride jaune, on its voyage from Bangkok, disregarding the fact
that the ship, blown out of its course, called at a port in Brazil where yellow
H. HAROLD SCOTT.
173
fever was raging before coming on to Martinique. AuGusTIN affirms also
that Smyrna was an original focus because remittent fevers of antiquity devastated the Grecian Archipelago and the shores of Asia Minor.
The chief supporters of the American origin are FiNLAY (CARLOS FINLA¥,
not our famous G. M. FINDLAY who has done so much recently in elucidation
of yellow fever problems), CAIZERGUES, KERMORGANT, JORGE, and RUBERT
BO¥CE. HIRSCH and CHABERT I regard as neutrals. Let us take the proAmerica view first. The reasons given are these : - 1. After the battle of Vega Real, in March, 1494, a serious outbreak
of disease took place among COLUMBUS'S men, with loss of one-third of
them~
FINLA¥, by a process of exclusion, maintains that this was 'yellow fever
because other diseases with high mortality--typhus, plague, smallpox and
choleramwere known to Europeans and would have been recognized by
COLUMBUS.
2. New colonies established by survivors of the San Domingo
epidemic of 1493 (who, consequently, would be, say they, immunized),
namely, Porto Rico and Jamaica in 1509, and Cuba in 1511, did not suffer
any loss.
3. The term xekik, a name given to a Mexican disease in preColumban days, means " vomiting of blood " and is translated, after
1648, as " black vomit," and an old Mayan manuscript, says a translation
of the seventeenth century, contains a medicine for " Xekik, with black
blood like an infusion of soot." Cocolitztli is another Mexican disease,
or an alternative name for the same disease, and is referred to before the
coming of Europeans.
4. The coup de barre epidemic in Guadeloupe in 1635 is regarded by
FINLAY and by BI~RENGER-F~RAUDas yellow fever.
5. Expeditions to tropical America often suffered a high mortality.
6. Navigators iflake no mention of any disease like yellow fever on
the West Coast of Africa prior to the discovery of America. Accounts
begin to be suspicious in the middle of the sixteenth century and become
more certain in the seventeenth.
7. Communication between Europe and West Africa was fairly
frequent in the sixteenth and seventeenth centuries, and the disease, if
it had existed in Africa, would have often been imported into Europe.
8. The slave-trade was not well established till the seventeenth
century, whereas, say FINLAY and B~RENGER-FI~RAUD, yellow fever has
been shown as existing in America ever since the fifteenth and sixteenth
centuries.
Before we go more deeply into the question let us clear the ground of some
of these dicta, may we call them, for they are little more ? The prime difficulty
174
SLAVE TRADE AND TROPICAL DISEASE.
is that descriptions of disease in the early days were by laymen, the symptoms
are not clearly portrayed, false causes are alleged and believed without investigation, and we have, therefore, to rely largely on epidemiological factors and
data--mortality, climatic conditions, acclimatization, etc.
The first of these reasons, the outbreak among COLUMBUS'S men after
Vega Real, we have already dealt with. The second, the establishment of
new colonies by survivors of the San Domingo epidemic without loss by disease, has little weight. The absence of the disease is just as likely to have been
due to non-introduction of infection as to the infection being present and the
people immune. Next, the terms cocolitztli and xekik, especially the latter as
meaning " b l a c k vomit." This name was given in 1648 to an outbreak which
occurred in Mexico at the end of the fifteenth century, i.e., at least 150 years
earlier. Xekik, it is true, means , vomiting of blood." The disease called
by the translator xekik was known in the country certainly before the Spanish
conquest, but in my belief the translator read back, as it were, his then present
views into a past outbreak which the true facts hardly warranted. Records at
the time of the epidemic called it maya cimil, and cimil meant not " vomiting
of blood " (xekik), but " death from pustules," and, therefore, almost certainly
smallpox and, if there was bleeding, then haemorrhagic smallpox, and the
claim that it was yellow fever peters out. Cocolitztli was a much vaguer term ;
it was used for smallpox in 1520 and 1538, for measles in 1531, for typhus in
1526, 1545, 1563, 1576 and 1595, and even for deaths from famine in 1558.
To translate it, therefore, as a p p l y i n g t o yellow fever is no proof whatever
that the disease was of that nature. Fourthly , the coup de barre outbreak in
Guadeloupe in 1635. That this was yellow fever has been based solely on
the opinion of Du TERTRE, an historian and 'a Roman Catholic priest. The
term means a blow with a stick, or the pain due to a cudgelling, and nobody
now, I believe, regards it as having been yellow fever. The mortality was
low; I suggest it was an outbreak of dengue. Fifthly, that expeditions to
tropical America often suffered a high mortality is an argument too vague to
call for serious refutation from the yellow fever point of view ; the cause might
equally well be malaria, or typhus, or dysentery, to name but a few. FINLAY'S
sixth reason, that navigators make no mention of any disease like yellow fever
on the West Coast of Africa prior to the discovery of America and that accounts
begin to be suspicious in the sixteenth and seventeenth centuries, I will speak
of in a minute or two. His penultimate reason, that if yellow fever had existed
in Africa in "these two centuries, seeing that communication occurred between
that country and Europe, why was not the disease imported into Europe, is
very weak, and is rather on the lines of KINC CHARLES II's conundrum about
the weight of a fish in and out of a bucket of water. For the answer is that
history shows that it was so imported, to Gibraltar and Cadiz, for example,
though scarcity or absence of vectors limited its spread. Lastly, that the slave
trade was not well established till the seventeenth century, whereas yellow fever
H. HAROLD scoTT.
175
existed in America in that and the preceding. This is an easy one to answer.
I n the first place the slave-trade was brisk in the sixteenth century; in the
second the statement is a direct petitio principK.
A word on two on his " biological arguments." He avers that the mildness of the disease among negroes is not due to acquired immunization, but is
a racial characteristic, a degree of natural immunity. This again is rather
begging the question, but there seems to be some truth in it. The pure negro
does seem to be less susceptible than mulattos, quadroons and octoroons,
though others have observed that natives who travel to Europe, not having
had the disease, are equally susceptible with the whites on returning to a yellow
fever country, and negroes in non-yellow fever districts are as susceptible as
non-immune Europeans, as shown in the Barbados and St. Kitts outbreaks of
1646. On the other hand, EVSAGUIRRE noted in. the middle of last century
that the Chinese settled at Lima were, like the native negroes, almost exempt
from the disease.
CAIZERCUES, writing in 1817, bases his opinion that the disease was originally American on the statements of the Philadelphia College of Medicine as
to the close relationship between yellow fever and bilious remittent fever, now
known to be erroneous. According to this, he affirms : - 1. Yellow fever is merely the bilious remittent fever of warm countries
in a severe form and arises, like it, from putrefaction.
2. Yellow fever and bilious fever are rife in the same months and
subside at the same times of abundant rain and cold weather.
3. They are of the same nature and differ only in degree, and one may
pass into the other. " Yellow fever by use of purgatives," h e says, " may
become ordinary bilious fever, and by use of unsuitable tonics ordinary
bilious fever may assume all the symptoms of malignant yellow fever."
4. They are equally contagious under similar atmospheric concurrences.
5. Since 1793 (the date of the famous Philadelphia outbreak) the
constitution of the air has imparted an inflammatory character to all the
prevailing }tiseases.
6. Yellow fever is due to local causes such as putrescence from canals,
streets, etc., and to vessels loaded with vegetables in a decaying state.
7. If it be said that cases occur in persons who have not been exposed
to imported contagion, we can only reply that miasmatic contagion is very
subtle and similar inexplicable cases occur, for example, in smallpox.
CHABERT,though he wrote much, contributes little, alluding to the confusion that there was between yellow fever and typhus, putrid fever, continued
ataxic fever, intermittent and remittent bilious fever, abscess of the liver (he
quotes Professor TOMMASINI in support of this), primary phlegmasia of the
176
SLAVE TRADE AND TROPICAL DISEASE.
stomach (in the words of Professor GIRARDIN, who held that sporadic yellow
fever was essential for acclimatization) and scurvy (on the authority of Dr.
DALMAS). He himself makes the not very useful suggestion that yellow fever
is due to " gastricity and phlogosis."
At one time, authorities on yellow fever, states R. JORGE in his monograph, would call the disease American typhus, accepting the American origin
as a truism, thinking they solved the problem by thus cutting the Gordian
knot. Other points which JORGE adduces are that the description by LOPEZ
DE COGOLLUDO of the Yucatan outbreak of 1648 is a clear-cut picture of yellow
fever (but there is no mention of icterus) and that the first description by a
medical man, mentioning jaundice and black vomit, is that of the Portuguese
FERREIRA DA ROSA on the Pernambuco outbreak of 1685-93. JORGE affirms--:
but I can find no evidence to Verify it--that the negro in America is almost
immune, whereas in Africa he is readily attacked, and he goes on to say that
" one must reject the idea that immunity among the negroes is acquired ; all
evidence goes to show that it is a racial gift," i.e., a natural immunity:
KERMORGANT states categorically, clearly taking it as established and indisputable, " the disease originated in the Gulf of Mexico, where it was known
since the discovery of the New World. Next, it made its appearance in the
Antilles, the eastern and western coasts of North and South America, and finally
the West Coast of Africa and, at times, in Europe."
Lastly, Sir RUBERT BOYCE, in his three chief works--Yellow Fever and its
Prevention ; Mosquito or M a n ? and Health Progress in the West Indies--states,
in the first, as if it were a settled fact, that yellow fever was primarily a New
World disease, and he repeats it in the others. Nowhere does he attempt to
discuss the question. The opening words of his book on yellow fever give
his view quite clearly : " The fragmentary historical evidence which we possess
tends to show that yellow fever existed among the native races of Central
America when the Spaniards arrived. It is stated to have been known to the
ancient Mexicans. It was found in Columbian times amongst the peoples
inhabiting the New World. Centuries afterwards evidence .points to a similar
endemic foothold on the West Coast of Africa." He seems to regard it as an
endemic disease in various places from the beginning. Thus, " Yellow fever
was one of the established indigenous diseases when the early explorers arrived
(in Central America) from E u r o p e " (page 4). " In British Honduras yellow
fever was no doubt endemic in the early part of the seventeenth century at the
time of its settlement in 1630 " @age 6). " We can, I think, come to no other
conclusion than that yellow fever was endemic in these [West Indian] islands
at the time of their invasion by the Latin races in the sixteenth and seventeenth
centuries," and he mentions Cuba 1620, Guadeloupe 1635, St. Kitts 1648,
Barbados 1649, and so on, but, strangely enough, he says (page 15), " In the
case of Barbados, the fever attacked the coloured and black population with
more frequency than the white " ; therefore, surely, a new disease, or, as BoYcE
H. HAROLD SCOTT.
177
puts it, " endemial fever had long ceased to exist," without offering any evidence
that it had been present there before. Again, speaking of Grenada, " Yellow
fever is said to have been introduced in 1793 from West Africa and, in consequence, was called Bulam fever.
It certainly could have readily been introduced; but in all probability the fever was naturally endemic to this as to
other islands of the group." This is mere conjecture unless some evidence is
adduced in support. One last quotation from this work : On page 48 BoYcE
states that whether yellow fever was first endemic in the West Indies or in
Central and Southern America, the conclusion is that it was endemic in both.
Also, " yellow fever was in all probability a disease endemical to the _native
races of the coast " [of West Africa]. BO¥CE perhaps brings one point as evidence, but it is of little worth. In Mosquito or Man ? he writes : " There is
every reason for supposing that yellow fever is one of the very old diseases of
mankind in the New World. It is stated that it was known to the Aztecs under
the name matlazahuatl." But, says HIRSCH, who had gone into the question,
there is no reason " for identifying with yellow fever the Mexican pestilence
. . . under the colloquial name of m a t l a z a h u a t l . . , for it was prevalent
almost exclusively among the natives of the country and it affected only the
interior and the tableland of Mexico, sparing the coast regions . . . .
It can
hardly be doubted that it was typhus."
The evidence in favour of the African origin or, more correctly, the source
whence other parts of the globe became infected has fewer supporters but, it
appears to me, they have'the greater weight of evidence. (If I may apply a
Latinism, I would say that those in favour of the American origin are multi
and their evidence multa non multum, whereas the pro-African evidence may
be spoken of as multum though the advocates of it are non multi.) This
evidence may be ranged under two main heads (1) Epidemiological, including
historical; and (2) Biological or entomological. Let us take it in that order.
It is generally acknowledged that the first intelligible account of undoubted
yellow fever was that of Fray Diego LOPEZ DE COGOLLUDO describing cases
in Yucatan in 1649 and the first detailed account of an epidemic in the New
World that of the Fever of Olinda, a seaport of northern Brazil, in 1685-86,
whereas the first to describe the disease in West Africa was SCHOTTE who, in
1780, gave an account of the 1778 outbreak at St. Louis, Senegal. It is not easy
to say now what was the nature of the earlier epidemics in the New World
for they were recorded briefly by military or other no,n-medical men who
merely noted them as interfering with their expeditions of conquest. They
used vague terms such as una peste, una fiebre pestilencial, el contagio, la epidemia
and the like, occasionally one more specific, la modorra, meaning lethargy or
stupor, more likely to have been cerebral malaria or enteric fever than yellow
fever.
Records of times before the Spanish Conquest in 1519, the Nahuatl records
during the Conquest and for half a century after it, and those of later Spanish
178
SLAVE TRADE AND TROPICAL DISEASE.
historians describe nothing which seems to me to resemble yellow fever, and
the disease mentioned by COLVMBUSas occurring in 1493 was almost certainly
malaria; at all events it was not yellow fever. Further, the outbreaks which
these records do mention are ascribed to famine and cold and occurred in the
tierra fria, the cold country, where yellow fever, if introduced, would not be
like!y to spread. Moreover, as far as can be made out the symptoms were not
those of yellow fever. T h a t of 1520, known as tohtomonatiztlil was so serious
in the city of Mexico that CORTEZ abandoned the place. The word means
" having pustules," and was almost certainly smallpox, as was that of 1538.
The outbreak of 1531 went by the name sarampidn, i.e., measles, also very fatal,
as it usually is when first introduced into a country, e.g., East Africa in the
1830's, as recorded by LIVINGSTONE,and in Fiji in 1874-75, when 40,000 died
of it. In 1545, 1563 and 1596 very severe outbreaks occurred with high fatality,
but the symptoms differed much from those characteristic of yellow fever.
Why they have been taken for granted as yellow fever I cannot imagine. The
most striking symptoms were fever and profuse haemorrhage from mouth,
nose and anus. In Mexico alone 800,000 are said to have perished, in Tlaxala
150,000; one outbreak was prolonged during the cold season--itself a fact
militating against its being yellow fever. TORQUEMADAestimated the total
deaths at 2,000,000, and he called it tabardillo, a spotted fever of the typhus
group. It was also known as mathaltotonqui or " blue-green fever." It may
have been haemorrhagic smallpox, typhus, or louse-borne relapsing fever, or
all three ; whichever it was, the point material to my thesis is that it was not
yellow fever. Moreover, the Indians were the chief victims, not the Europeans,
a strong point against its being yellow fever. In 1550 an outbreak known as
paperas had a high fatality. Paperas means swelling of the neck and seems to
have been some form of severe angina with adenitis, possibly diphtheria; it
would appear to have been too severe for epidemic parotitis. Lastly, at least
the last I need mention, is that of 1595 when there was a serious epidemic"
said to be a mingling of paperas and tabardillo, or, as I would interpret it,
anginal sore-thrSat, perhaps diphtheria, and typhus.
Two sorts of outbreaks are described by what we may call the Conquest
group of recorders, one smallpox, the other characterized by " throwing off
of blood by nose and mouth," very like the fatal cases in the 1918 pandemic
of influenza with complicating pneumonia. In all HERRERA'S writings I can
find no disease with symptoms characteristic of yellow fever.
So we come to the 1648 outbreak referred to already ; this was undoubtedly
yellow fever, the description is remarkably clear. The natives and Europeans
(Spaniards) were equally attacked and the whole reads as a classical account of
yellow fever among a non-immune population and there is little doubt that
infection had been brought in vessels sailing between Campeche and Vera
Cruz. Before the recent " protection t e s t " the most trustworthy criterion of
endemicity was the degree of liability of t h e people to contract the infection when
H. HAROLD SCOTT.
179
the virus was introduced. Judged by this standard Cuba had no yellow fever
for 125 years after it was occupied; then an outbreak occurred which, it is
recorded, carried off a third part " of the garrison and civilians, that is natives
as well as Europeans.
As regards the claim that records from the New World preceded any
from West Africa, this is not disputed. COGOLLUDO'Saccount of the 1648
outbreak preceded that by SCHOTTE of the Senegal outbreak by 130 years,
but this has little weight as favouring priority of infection in the former, because
COGOLLUDO shows that the natives were as susceptible as the Europeans, and
failure to describe it earlier in Africa finds a ready explanation in the paucity
of Europeans and the fact that most of these were soldiers or convicts, incapable
of describing it. Moreover, communication between Africa and the New
World was frequent in the two centuries preceding COGOLLUDO'S account.
Thus, in 1503, OVANDO, the Governor of Hispaniota, had asked that no more
negroes be sent there, as they were " already too numerous for good order."
Again, from what is known--the point has been referred to earlier--the Indians
of America exhibited no immunity, but contracted the infection as readily, a n d
in general had as high a fatality rate, as the white men.
The history of the slave-trade itself gives no little help in solving the
problem. The trade from Africa was started by the Portuguese in 1441, the
slaves being obtained from the mainland. In 14/I8 the Bay of Arguim was
their trade base ; Elmina in 1482 and Angola in 1490, became centres of collection and their ultimate distribution sites were tropical America and the
Spanish settlements. Between 1581 and 1640 Spain and Portugal were under
one sovereign, but at first Portuguese vessels only might enter Portuguese West
African ports and only Spanish vessels could trade with the Spanish ports of
America. S~o Thiago, in the Cape Verde Islands, was constituted the intermediate distributing centre, slaves from ports not under Portuguese control
being taken to French, Dutch and English colonies in America. The outbreak
of 1585, which proved so disastrous to DRAKE'S expedition at Sgo Thiago,
according to the description available, was typical yellow fever, and Sir RICHARD
HAWKINS, writing of the Cape Verde Islands in ELIZABETH'S time, notes their
unhealthiness: " In two times that I have been in them, either cost us one
half of our people with fevers and fluxes . . . and in one of them it cost me 6
months' sickness with no small hazard of life." A~des might easily be imported
from the Gt~inea Coast to S~o Thiago ; the drinking water was rain, which
was stored on board, and in the dwellings.
In the Gambia there have been epidemics of fever at least since the fifteenth
century. We cannot say that these were o r were not yellow fever, but there
seems to have been no change in their general character before or after the
slave-trade started, or before or after the discovery of America. Lastly, there
is indirect evidence that the disease was new to the West in the fact that so often
and in so many places the people had no name for it, calling it merely by the
"
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SLAVE TRADE AND TROPICAL DISEASE.
name of the place whence they thought it had been brought, such as maladie
de Siam, Bulam fever, Olinda fever, Oriflamme fever (the name of the vessel
introducing infection).
Summing up the historical evidence we must, when all is considered,
conclude by saying that positive evidence is not sufficient for us to affirm beyond
all doubt where human yellow fever originated. Owing to paucity of records,
confusion of diseases, to the writers being non-medical, we really cannot say
what actually were the pestilences before the arrival of Europeans. The statement that America was probably the primary site because jungle yellow fever
occurs there and not in Africa is totally unwarranted.
Turning to the biological or entomological argument, A. W. SELLARDS,
in STITT'S great work, states: " Presumably both the virus and the insect
vector (Aed. aegypti) were brought to the New World during the days of the
slave trade. [I do not like " presumably," it Often presumes too much.] On
entomological grounds the aegypti mosquito appears to be an importation
into the New World since there are many species of mosquitoes more or less
closely allied to A. aegypti in Africa, but no other member of the subgenus
Stegomyia which i s native to the Americas." JORGE goes even further, and
says that America had no Stegomyia in pre-Columban days, and that the
mosquito was imported thither in ships from African ports. We may compare
this with the importation of Anopheles gambiae in modern times. Again, in
America later there was one species only, Aides aegypti, in Africa several, and
therefore, he argues, Africa is the plac e of origin of Aides. But, and this is very
important, aegypti is not the only Aides in America, at all events now. Aides
crinifer, scaputaris, nubilus, fluviatilis, terrens and fulvithorax exist there ; some
of these are infectable experimentally, and scapularis is believed to have been
the vector in the Chanaan outbreak. Aside altogether from this is the fact that,
fortunately, the geographical distribution of yellow fever does not correspond
with the distribution of its usual vector. Why has Asia remained exempt,
why China, why most of the Mediterranean coast, except Leghorn ? We do
not know ; the Athens outbreak of dengue shows the prevalence of A. aegypti,
and vessels must often have come there from Africa and America.
Whether yellow fever had its origin in West Africa or in the New World
is important in so far as the incrimination of the slave-trade as introducing the
disease into America is concerned, but it is immaterial as regards the w i d e r
question whether the trade was the cause of the spread of infection, for whether
it was carried from Africa to America or brought back in ships returning from
America to Africa, to the West Indies, to Europe, the slave-trade was the means
of effecting the extension.
LEPROSY.
It is not possible to declare with certainty in what country leprosy originated,
but study of available records points to its first home being Africa, the belt of
H. HAROLD SCOTT.
181
land extending across the Continent from Nigeria to Abyssinia, the country
where its endemicity is greatest today. BRUGSCH, in his Histoire d'Egypte,
mentions that it was prevalent in Egypt in the reign of HUSAPTI, 2400 B.C.,
and we know that it has been common in Africa, Egypt and India for the past
3000 years and that it was re-introduced into Egypt by negro slaves brought
from the Sudan in the time of RAMESES II, 1350 B.C.
Its introduction into Europe does not concern us now, except perhaps as
regards Spain and Portugal. To these it was brought first by Phoenician
traders. Rgme and Italy generally owe its presence primarily to Pompey's
soldiers returning from the East in 62 B.C., and again, nearly 2,000 years later,
to immigrants returning from Brazil and other parts of America. The Romans
spread it to Germany at the end of the second century, whence it extended to
Spain in the fifth and sixth centuries and to France by invading Saracens in
the eighth century. Generally speaking, we may say that in Europe and the
East extension has been the result of immigration, to Ipdo-China, Siam, Java,
Sumatra, Borneo, the Philippines and Malaya, largely by the Chinese. Strictly,
I suppose, as Egypt was infected by slaves from the Sudan nearly 3,300 years
ago, this should be included in my thesis, but I propose not to go outside the
slave-trade between Africa and the New World. West Africa itself, it is generally believed, became infected by slaves or immigrants from the Sudan and,
with opening up of the interior and increase of commerce, the disease spread
rapidly.
America became infected from four sources: Europe, Asia, Africa and
the West Indies. CHICO, the only writer I know of who affirms that the Spaniards
at the Conquest of Mexico in 1519 found cases among the natives, was probably
misinformed; JULIANO MOREmA, who has gone deeply into the question,
has concluded that these were more likely cases of mal del pinto. It is now
generally admitted that America was free from the disease until the Spaniards
and Portuguese introduced it; and when the slave-trade became a thriving
industry the negroes who were brought over included hundreds, perhaps
thousands, of lepers, and after emancipation of the slaves indentured Indians
and Chinese introduced yet more.
The/story is similar in many of the Spanish colonies and settlements, the
slaves being not the primary but the secondary introducers and far exceeding
the former. Thus, Louisiana was infected by early settlers from Spain, next
by slaves from Africa, later still by Acadians from Nova Scotia, and imported
slaves from the West Indies in the middle of the eighteenth century. HANS
SLOANE reports seeing cases in Jamaica in 1687. Portuguese emigrated with
their slaves from Brazil to Dutch Guiana in 1694 and within a decade other
slaves were being imported from Africa to work on the plantations and within
70 years lepers had become so numerous that regulations had to be made forbidding them the streets of the towns, and in 1763 further importation of lepers
was prohibited. SCroLLING, in his thesis on leprosy in 1768, noted that of
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SLAVE TRADE AND TROPICALDISEASE.
the indigenous natives only those suffered from leprosy who had had contact
with negroes from Africa. French Guiana is believed to have been free from
the disease until slaves from Africa brought the infection in the seventeenth
century, and the same applies to British Guiana. In Colombia the first recorded
cases were among Spaniards from Andalusia; in 1573 " it was verified that
Don GONZALO JIME'NES DE QUESADA, the founder of the town of Bogota, was
a leper." Later, African slaves introduced more. Evidence goes to show that
it was not the slave trade but the introduction of Indian and Chinese labour
that was responsible for most of the leprosy in the Pacific Coast States.
Leprosy in Brazil presents a problem of no little interest. It was not
known at the time of the discovery of the country in 1500 by the Portuguese
Admiral CANRAL ; there is no mention of it in the letters of VAZ CAMINHA
which give detailed accounts of the country and people; GABRIEL SOARES E
SOUZA in 1587 speaks of bouba (yaws) but not of leprosy, nor do the travellers
SAINT-HILAIRE, 3/IARTIUS, KUPFFER, ORBIGNY, HUMBOLDT mention it, nor does
Plso in his medical report of 1648. H o w , then, was it introduced, for it is
prevalent enough in certain districts now ? Not primarily can it be accredited
to the slave-trade, and even subsequently in part only. Slaves were first brought
there from Africa in 1583 and in greater numbers in succeeding years, but,
nonetheless, leprosy, if present at all, was not common, because, according to
FERNANDO TERRA, these slaves had come from the interior a n d parts where
leprosy was comparatively rare. There is little doubt that the early introduction
was mostly by the Portuguese themselves from Europe and, to a less degree,
by the Dutch, French and Spaniards. As early.as 1419 leprosy was common
among the Portuguese in Madeira and the Conquistadores were the-first to
introduce the infection. Not only in Madeira but in Portugal itself leprosy
was known to be very prevalent at the time ; as for the French contribution,
marines coming to Brazil between 1555 and 1700 were recruited chiefly from
Normandy, Pas-de-Calais, and Brittany, and the disease was rife in Normandy ;
in fact, French sailors from Normandy brought leprosy to Canada. Slave
importation, however, greatly added to the number of lepers. By 1630, less
than half a century after the trade had included Brazil, practically one-fourth
of the population (14,000 out of 57,000) were slaves from Africa. The ports
of entry, Rio de Janeiro, Bahia and Recife, showed t h e highest prevalence, so
much so that by 1637 an appeal for control of lepers was put forward in Rio
de Janeiro. By 1710 half Rio's population of 60,000 were slaves, and by 1851,
of the population of the Province, a little over half a million, nearly 300,000
were slaves.
In the case of the West Indies the story is very similar to that of South
America--primary introduction by Europeans, Spaniards and Portuguese,
when the islands were colonized and traffic arose between the islands and the
mainland. The actual introduction is supposed to have taken place from
Martinique or Cuba about 1776. Later, of course, much wider extension was
brought about by the slaves imported directly from Africa.
H. HAROLD SCOTT.
183
YAWS.
It was the widely, if not generally, held opinion at the beginning of the
nineteenth century that yaws originated in West Africa and that the slavetrade was the means of importing the disease into other places where it is now
endemic. Even at the end of the last century J. S. WALLBRIDGE and C, W.
DANIELS, in their consideration of NICHOLL'S report on yaws in the West
Indies, state categorically : " The disease, as far as the West Indies are concerned, is of African origin," but DANIELS goes on to say that the West Indian
yaws is identical with the coko of Fiji, a n d h e saw many cases of both. Deeper
investigation throws much doubt upon this; in fact, from all the evidence
I have been able to obtain, it would appear that, when tropical medical history
began, pian, framboesia, yaws existed in many regions of the world as far apart
as the east is from the west. OVI~DO Y VALD~Z (1478-1557), in his Historia
general y natural de las Indias records meeting it in Hispaniola ; PlSO in 1648
notes it in Brazil, under the name bubas; LABAT in the seventeenth century
speaks of it in the West Indies, and BONTIUS (1592-1631) in the East Indies
at the beginning of the same century. The essential difficulty in coming to
a definite decision arises in the fact that nearly all the references to it are in
the writings of the late eighteenth or early nineteenth centuries, by which
time negro importation had been going on for 250 years or more. But the
fact of its prevailing in the East--the Moluccas, Java, Sumatra, Celebes, Fiji
and Samoa--militates strongly against the view of West African origin. OVIEDO'S
account, moreover, refers to Hispaniola at the time of its first colonization
by the Spaniards prior to any negro importation, and SmAUD, writing on the
diseases of Brazil, speaks of a manuscript in the Royal Library at Rio de Janeiro,
and dated 1"587, which treats of yaws in that country.
The fact--it appears' to be factual=--that the disease was present in the
West before Columban days concerns, of course, the question of its primary
introduction only ; there can be no doubt that importation of infected slaves
would contribute much towards spreading the disease, for it is known that
epidemics of it occurred on slave-ships. During slavery days fresh cases were
being constantly imported and they became so numerous that they were segregated in " yavCs houses " in many West Indian islands. (There was some
confusion at times between yaws and leprosy and the same houses were used
for both.) After emancipation these houses were abandoned, the inmates
scattered and became loci for other cases all over the country. We may sum
up by saying that yaws was probably autochthonous in Hispaniola, Brazil,
Fiji, Samoa and West Africa, and imported into the West Indies by slaves.
TRYPANOSOMIASIS.
African trypanosomiasis, negro lethargy, was certainly carried to the West
Indies by slaves, but the fact was noticed that the creoles were never attacked,
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SLAVE TRADE AND TROPICAL DISEASE.
only the negroes, and of these.only such as had themselves been brought over
as slaves, that is, others born in the islands, even if their parents were victims,
were not attacked, though the disease might not show itself until the subjects
had been in the islands for a considerable time. The natives themselves in
Africa were aware of the significance of the enlarged glands in the neck-known later as Winterbottom's sign--for the Mandillgoes in the Gambia used
to " cut the neck-stones of the boys to prevent the occurrence of sleepingsickness later in life." Whether the operation was effectually preventive I do
not know, but I imagine not.
Several writers have recorded cases in the West Indies and South America.
MOREAU DE JONN~S in 1808 saw them among slaves in the Antilles, as did
DANGAIX in 1861 ; NICHOLAS in 1863 saw five cases among 1,200 negroes in
9 months and he thinks that one in every 100 deaths among negroes on the
voyage from the Congo to t h e West Indies was due to negro lethargy. GAICNERON and GRIFFON DU BELLAY recorded others 2 years later, and GUI}RIN,
of Martinique, in his Paris thesis, 1869, noted 148 cases among slaves imported
from the Congo in the course of 12 years. GORE had seen cases among negro
soldiers in the Bahamas, and RIBEIRO among negro labourers in Brazil. These
were all cases which had escaped recognition in the early stages, for the traders
knew the symptoms and the high mortality among those affected and refused
to buy negroes with swollen neck-glands.
The slave-trade, therefore, was
responsible for transporting cases, but not for spreading the infection in the
West because, fortunately, there were no suitable vectors, no Glossina, in the
New World.
I do not know whether reduviid bugs exist in West Africa--entomologists
will be able to tell us--if they do not this fact may, analogously, explain why
Chagas's disease, as we now call it, American trypanosomiasis, was not brought
from South America to Africa, bearing in mind, of course, that until Sierra
Leone was founded as a slave settlement and Liberia established for repatriated
slaves in 1820 the traffic in slaves was a one-way traffic only.
LEISHMANIASIS.
As I have said above, we must guard against the inference that because
a morbid condition, or a causative organism, is found in Africa and in the
New World the latter became infected by importation from the former. A
good example is cutaneous leishmaniasis. It is present as bouton d'Orient in
the East, in Asia Minor, along the Mediterranean littoral, in Southern Russia,
India, China (Hunan), in Africa, Tunisia, Egypt, the Sudan, the French Congo,
Nigeria and the West Coast down to Angola; in the New World it occurs
in Brazil, Peru, Guiana, Paraguay, Bolivia, Silo Paulo, the Argentine and
Mexico. That it can be transported is proved by J. N. WRIGHT'S case: he
saw in Boston a child who had come over from Armenia and was thought
H. ItAItOLD SCOTT.
18S
to have contracted the infection there. Though the dates of all these recordings
in the New World are Of the present century, the condition must be of old
standing in South America, for ancient Inca pottery depicts figures with the
facial mutilations of espundia.
Mal del pinto has a fairly wide distribution in the New World--Mexico,
Colombia, Venezuela, Ecuador, Chile, Peru, Guatemala, Brazil, C u b a - - a n d
some have thought that, as a spirochaetal disease, it might be grouped with
yaws, prevalent among slaves brought to America. There seems to be little
to support this, for we never hear of a case in the negroes of Africa. It may
well be that the slave-trade did assist in its spread by transporting from one
part of the New World to another slaves who had already acquired the disease,
from Cuba to Brazil for example, but this is pur e hypothesis.
DENC~JE.
As regards dengue, there must be more than a little doubt. We are usually
:given to understand that the earliest account of the disease is that by GABERTI
of the outbreak in Cairo in 1779, but I for one do not feel convinced that this
was dengue. He calls it real de genoux, but mentions neither secondary fever
nor rash. Though these may not always be present, it is unlikely that they
would be absent from all, or even the majority of cases in one outbreak. RusH,
of Philadelphia, was the first to describe it clearly under the name " break-bone
fever " in 1780. From the early years of the nineteenth century outbreaks were
reported from many tropical and subtropical regions--India, Spain, Tripoli,
North and South America, the West Indies. I have only one suggestion in
s u p p o r t of the possible transference of the disease by a slave-ship and this is
the Guadeloupe outbreak in 1635, which, if it was dengue, antedated GABERTI
and RUSH by nearly a century and a half. I refer to what was called coup de
barre, which some authorities, as I have already mentioned, have regarded,
and do still regard, as yellow fever, in my opinion on very inadequate grounds.
The disease was characterized by violent headache, throbbing vessels, difficulty
in breathing, pain in the limbs and a feeling of general bruising, as after a
cudgelling--hence the name. The mortality was low, itself contra-indicating
yellow fever. Another argument sometimes adduced is that it was not a new
disease even then, for the natives had a name for it, iepoulicdatina. This, too,
means a blow with a stick and is just as likely to be a Carib adaptation of the
French term as coup de barre the French equivalent o f / h e Carib word.
SMALLPOX
Mention may be made in passing--I am not going to discuss it--that
according to CHISHOLM smallpox, whether mild or confluent and malignant,
has " in every instance been introduced [into the West Indies] from the coast
of Africa by slave ships."
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SLAVE TRADE"AND'ITROPICAL DISEASE.
HELMINTHIC INFESTATIONS.
Lastly, there are certain helminthic infestations which owe their spread
to the slave-trade, forms "of filariasis and rectal schistosomiasis. One or two
of these may be considered briefly--time limits my going into the subject in
detail.
Wuchereria bancrofti is very widespread. RHAZESand AVICENNA, Arabian
physicians, wrote of it in the ninth and tenth centuries, and it is said to have
been known to Hindu writers 1,500 to 1,600 years earlier. It is found in North
and South America, in Australia, India, South China, Japan, the Dutch East
Indies, Samba, and in West and Central Africa. We cannot even conjecture
the original home of this w o r m . DEMARQUA¥, in Paris, was the first to demonstrate the embryo in the hydrocele fluid of a patient from Havana in 1863;
WUCttERER three years later found it in the chylous urine of a man from Brazil-;
LEWIS, in 1872, in the blood of a H i n d u in India ; the adult worm was seen
by BANCROFT in, Australia in 1876-77, and MANSON in Amoy worked out its
fife-hist~ory, so the chain of discovery may be said to be cosmopolitan.
DANIELS discovered the adult of another filaria, Acanthocheilonema perstans,
in British Guiana, and MANSON the embryo in the blood of Congo natives in
1891. (For a time he was inclined to regard it as the cause of negro lethargy.)
It is very common in the Congo, Nigeria, Sierra Leone, the Gold Coast, the
Ivory Coast and the Cameroons; also in Rhodesia and Uganda, but these
do not concern us at present. It has been reported in South America, Venezuela
and Trinidad, in the Amazon Valley and northern Argentina. Considering
how prevalent it is, and was, in the slave regions of Africa there is a high degree
of probability that the trade initiated, it certainly fostered, the spread of infection.
Loa loa we may certainly regard as slave-imported. Loa loa, the eyeworm of Africa, was known to PiGAFETTAin the Congo at the end of the sixteenth
century, and MONCIN in 1770 removed one from the eye of a negress in Haiti.
Other cases, all in imported African slaves, were seen in Brazil, French Guiana
and Haiti. The infestation was, clearly, imported but whether it spread after
importation is less certain because all cases reported in the New World are
thought to have contracted the infection in the endemic areas of Africa.
Dracontiasis has been known for a long time. It is believed that the "fiery
serpents " which attacked the Israelites when Moses took them from slavery
in Egypt were Dracunculus medinensis and, according to STITT, it was suggested
that Moses taught the sufferers how to extract them by winding~ round a piece
of stick. His pupils, if so, do not seem to have been very apt because the fiery
part comes when the worm is broken by over-zealous or unskilful attempts at
extraction. PAULUS of Aegina mentions it, but does not think it is a worm
at all, but a nervous concretion resembling a worm and only appearing to
~move. PIGAFETTA, ever a keen observer (his seeing Loa loa has already been
~mentioned), saw it in the Congo and illustrates it in the account of his travels.
H.I-IAROLD SCOTT.
187
The endemic foci of Dracunculus are widespread : the Nile Valley, Uganda,
Equatorial Central Africa, West Africa, Persia, India. After it had been introduced into the New World cases began to be reported in the Guianas, the
Caribbean, West Indian Islands, San Domingo (by PER~ and POVPP~-DEsPORTES),
Jamaica (by S LOANE), Barbados (by HmLARY) and Martinique (by SARAV~SY)
and in Southern Brazil. These records all come from the time when negroes
were being imported from West Africa. Since the importation ceased, there
have been practically no more reported cases, except from a very few centres
of which Curacao appears to be one and Feira da Santa Anna in the Province
of Bahia another. This last is particularly interesting because in 1849 two
caravans encamped by a stream there and, though warned against it by the
natives, the travellers used the water f o r drinking (the record specially mentions that nobody bathed in it) ; a few months later all the party fell ill except
a negro who had refrained from drinking the water.
All writers on this infestation in Brazil, Guiana, the West and East Indies
and Egypt agree that dracontiasis was unknown there before negro importation
and after that time most of the cases recorded are in Africans. When the trade
ceased and with it intercourse between Africa and the New World cases became
fewer and from many of its former haunts none was reported. Infestation of
Bombay is attributed to imported negro troops; similarly, Madras in 1834,
but these have no connection with the slave-trade and nothing further will be
said about them now.
Schistosomiasis.--For a time after BILHARZ'S discovery of Schistosoma
haematobium in 1851, the laterat-spined ova were thought to be due to accidental distortion of the terminal-spined when passing through the tissues.
Then, in 1903, MANSON thought it must belong to a distinct species when he
found these eggs in the faeces of a patient from the West Indies who had never
suffered from haematuria. To trace the intermediate steps is not germane
to my subject; suffice it to say that the distinction was eventually proved
in 1916-18 by the experimental work and researches of Prof. R. T. LEIPER,
showing that the intermediary snail of the lateral-spined variety was a Planorbis,
a different genus from that of the terminal-spined, the Bulinus, and that the
two species of sehistosomes differed morphologically.
Schistosoma mansoni, it is generally agreed, was originally a West African
species, occurring in Senegal, French Guinea to Lake Chad, also in Liberia
and Sierra Leone, t h e Belgian Congo, Tanganyika and parts of East Africa.
Slaves brought from Africa have introduced it into Brazil, Venezuela, Dutch
Guiana, St. Kitts and other West Indian islands--St. Lucia, Nevis, Montserrat, Antigua, Guadeloupe and Martinique. In some of these the infection
rate is high. Incidentally, we may note that in St. Kitts the infestation is far
from uncommon in Cercopithecus sabaeus, the so-called " green monkey," itself
an importation from its home in West Africa.
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S L A V E TRADE AND TROPICAL D I S E A S E .
But I must not weary you. There is always a fear that when one is in a
position to talk without likelihood of interruption to a kindly audience one
may abuse the privilege. Besides the conditions I have mentioned there are
others, such as ackee poisoning due to ingestion of a fruit native to West Africa,
brought thence to Jamaica in a slave-ship in 1778 ; evidence in favour of the
African origin of alastrim and amoebic dysentery would provoke interesting
discussion, but my time is up and I end by expressing to you my gratitude
for your indulgence towards my desultory remarks and my hopes that this
attempt to take your thoughts for a short period from busy practice by delving
into the past has been both a relaxation and an interest.
Col. S. P. JAMES proposed a Vote of Thanks to the PRESIDENT for his
most interesting Address. This was seconded by Prof. P. A. BUXTON and
carried unanimously.